basic nuc physics
TRANSCRIPT
PHASESPHASE 1 STRUCTURE OF ATOM
PHASE 2 BINDING ENERGY AND MASS
DEFECT
PHASE 3 NATURAL RADIOACTIVITY,
ARTIFICIAL RADIOACTIVITY &
NEUTRON BOMBARDMENT.
PHASE 4 FISSION AND FUSION.
PHASE 5 CHAIN REACTION,CRITICAL
MASS AND REFLECTORS.
SCOPETO FAMILIARISE YOU WITH THE STRUCTURE OF ATOM, BINDING ENERGY AND MASS DEFECT, NATURAL AND ARTIFICIAL RADIO ACTIVITY,FISSION, FUSION, CHAIN REACTION, CRITICAL MASS AND REFLECTORS.
ELEMENT
AN ELEMENT IS A SUBSTANCE WHICH CANNOT BE SPLIT UP INTO TWO OR MORE SIMPLER SUBSTANCES BY THE USUAL CHEM METHODS OF APPLYING HEAT, LT OR ELECTRIC ENERGY. AN ELEMENT IS MADE UP OF ATOMS, ALL HAVING SAME ATOMIC NUMBER.
A MOLECULE IS THE SMALLEST PARTICLE OF A SUBSTANCE ( ELEMENT OR COMPOUND) WHICH HAS THE PROPERTIES OF THAT SUBSTANCE AND CAN EXIST IN FREE STATE.
MOLECULE
STRUCTURE OF STRUCTURE OFATOMATOM
•DEFINITION OF ATOM
•STRUCTURE OF HYDROGEN AND HELIUM ATOM
•ATOMIC AND MASS NUMBER
•UNITS OF ATOMIC MASS (M.U.)
•EINSTEIN`S MASS ENERGY RELATIONSHIP
•ISOTOPES
ATOM• AN ATOM CAN BE DEFINED AS
THE SMALLEST QUANTITY OF AN ELEMENT WHICH CAN ENTER INTO A CHEMICAL REACTION. ALL ATOMS OF A PARTICULAR ELEMENT ARE CHEMICALLY ALIKE BUT THEY DIFFER FROM THE ATOMS OF OTHER ELEMENTS.
STRUCTURE OF ATOM
NUCLEUSPROTONS
NEUTRONS
MASS CHARGENEUTRON 1.00898 m.u NO CHARGE
PROTON 1.00759 m.u + VE CHARGE
ELECTRON 0.000548 m.u - Ve CHARGE
STRUCTURE OF HYDROGEN ATOM
EMPTY SPACE SHELL
ELECTRON
10,000 IN(APPROX 1/6 MILE)
ATOM OF HYDROGEN MAGNIFIED 2.5 X 1012 TIMES
140 YD
1”
ATOMIC AND MASS NUMBER
• ATOMIC NO (Z) = NUMBER OF UNIT
POSITIVE CHARGES
= NO OF PROTONS = NO
OF ELECTRONS• MASS NO (A) = NUMBER OF PROTONS
PLUS NEUTRONS • NO OF NEUTRONS = A -Z
• SYMBOLIC REPRESENTATION- 2 He 4 ( Z He A )
UNIT OF ATOMIC MASS
UNIT OF ATOMIC MASS OR ATOMIC MASS UNIT (AM U) IS DEFINED AS 1/16 OF THE MASS OF OXYGEN ATOM AND IS EQUAL TO 1.66X10-24 GRAMS
CHARGE AND MASS OF ELECTRON, PROTON AND
NEUTRONPARTICLE SYMBOL AMU MASS CHARGE
GRAMS UNITS COLOUMBS
ELECTRON e- 0.000548 9.1 X 10 –28 -1 -1.60 X 10 -19
PROTON P+ 1.00759 1.672 X 10 -24 +1 + 1.60 X 10 -19
NEUTRON n 1.00898 1.674 x 10 -24 0 0
ISOTOPES• MTRLS HAVING SAME ATOMIC No BUT
DIFFERENT ATOMIC MASS No.
ISOTOPES OF HYDROGEN
1H1 - 99.985% - NATURAL HYDROGEN – LT
1H2 - 0.015% - DEUTERIUM (D) – HY
1H3 - VIRTUALLY MAN MADE -TRITIUM (T)
– 92U 238 - 99.3 % - NOT READILY
FISSIONABLE
– 92U 235 - 0.7 % - READILY
FISSIONABLE
– 92U 233 - ARTIFICIALLY MADE READILY FISSIONABLE
– ISOTOPE OF SILVER = 106.948 M.U
– TOTAL WT OF
• 47 PROTONS• 60 NEUTRONS = 107.944 MU
• 47 ELECTRONS
– MASS DEFECT = 0.996M.U.
BASICS OF NUC ENERGY• ALBERT EINSTEIN PROPOUNDED MASS AND
ENERGY ARE CONVERTIBLE AND EST THE FORMULA : E = mc2
WHERE, E = energy in ergs, m = mass in grams,
c = velocity of lt (3 x 1010 cm\sec) • NEUTRONS BEING ELECTRICALLY NEUTRAL,
CAN PENETRATE UPTO NUCLEUS OF AN ATOM AND LIKELY TO CAUSE BREAKING UP OF NUCLEUS.
• IN BEAKING UP OF AN ATOM, THERE IS CHANGE IN TOTAL MASS AND THE ENERGY THUS RELEASED IS ENORMOUS.
EINSTEIN'S MASS ENERGY RELATIONSHIP
E = MC 2
E = ENERGY IN ERGS – (10 7 ERGS = 1 JOULE )
M = MASS IN GRAMS
C = VELOCITY OF LIGHT = 3 x 10 10 CM/SEC
ERG - WORK DONE BY A FORCE OF 1 DYNE WHEN ITS POINT OF APPLICATION MOVES BY ONE CM IN THE DIRECTION OF THE FORCE.
COULOMB’S LAW
• LIKE CHARGES REPEL UNLIKE CHARGES ATTRACTS IN AN INVERSE SQUARE RELATIONSHIP
F = q1X q2
d2
WHERE, q1 AND q2 ARE TWO ELECTRICAL CHARGES MEASURED IN e.s.u. ; d THERE DIST APART IN cms AND F THE RESULTANT REPULSIVE OR ATTRACTIVE FORCE IN DYNES
BINDING ENERGY AND MASS DEFECT
• FORCES IN AN ATOM : COULOMB’S LAWF = q1 x q2 F = FORCE IN DYNES.
d2 q1 AND q2 = ELECTRIC CHARGES IN ESU.
d = DISTANCE IN CM.• MASS DEFECT
ATOMIC WEIGHT OF SINGLE PURE ISOTOPE IS LESS THAN SUM OF WEIGHTS OF INDIVIDUAL PROTONS, NEUTRONS AND ELECTRONS.– ISOTOPE OF SILVER - 106.948 M.U
(MASS NO - 107)
Contd…
– ISOTOPE OF SILVER = 106.948 M.U
– TOTAL WT OF
• 47 PROTONS• 60 NEUTRONS = 107.944 MU
• 47 ELECTRONS
– MASS DEFECT = 0.996M.U.
CONSIDER THE EXAMPLE OF FLOURINE( 9F 19)
– THE ISOTOPE HAS 9 PROTONS, 9 ELECTRONS AND 10 NEUTRONS.
• 9 PROTONS(9X1.00759) = 9.06831 amu
• 9 ELECTRONS(9X0.00055) = 0.00495 amu
• 10 NEUTRONS(10X1.00899)= 10.08990 amu
TOTAL = 19.16316 amu– KNOWN MASS OF THIS NUCLIDE IS 19.00445
amu.– DIFF BETWEEN KNOWN MASS AND THE
MASSES OF PARTICLES IS 0.15871 amu.– THE LOST MASS IS CONVERTED INTO
ENERGY AND IS CALLED MASS DEFECT.
BINDING ENERGY
BINDING ENERGY IS THAT AMT OF ENERGY WHICH WOULD NEED TO BE APPLIED TO A NUCLEUS TO BREAK IT DOWN INTO ITS CONSTITUENT NUCLEONS “STABILITY OF NUCLEUS CAN BE ASSESSED FROM THE VALUE OF ITS BINDING ENERGY PER NUCLEON. GREATER THE ENERGY PER NUCLEON, GREATER IS THE STABILITY”
20 40 60 80 100 120 140 160 180 200 220 240
BINDING ENERGIES PER NUCLEON
9
8
7
6
5
4
3
2
1
0
U 235
2H
1
2H
1
6L1
3
10B
5
MAX 8.7MEV
E
N
E
R
G
Y
(MeV)
MASS NO
UNITS OF ENERGY• ELECTRON VOLT(EV). KE GAINED BY A
PARTICLE CARRYING UNIT ELECTRICAL CHARGE,(e) WHEN ACCELERATED THROUGH A POTENTIAL DIFFERENCE OF ONE VOLT.
• UNIT ELECTRICAL CHARGE = 4.8 x 10 -10 E.S.U
• KILO ELECTRON VOLT - KeV 103
• MILLION ELECTRON VOLT - MeV 106
• BILLION ELECTRON VOLT - BeV (GeV) 109
IONISATION• IF AN ORBITING ELECTRON IS
PULLED OR FORCED AWAY FROM AN ATOM, THE ATOM, NOW POSITIVELY CHARGED, IS CALLED A POSITIVE ION AND THE PROCESS IS KNOWN AS IONISATION.THE DETACHED ELECTRON OFTEN ATTACHES ITSELF TEMPORARILY TO ANOTHER ATOM WHICH IS THEN A NEGATIVE ION.
NATURAL RADIOACTIVITY
• PROTON - NEUTRON RATIO
• TYPES OF RADIATION
• PENETRATING POWER OF
RADIATIONS
•RADIOACTIVE TRANSFORMATION
•RADIOACTIVE DECAY
NEUTRON-PROTON RATIOS OF STABLE NUCLEI140
120
100
80
60
40
20
0 20 40 60 80 100 120 140
NUMBER OF PROTONS (P)
NU
MB
ER
OF
NE
UT
RO
NS
(N
)
β EMISSION-EMISSION
STABILITY BELT
n/p = 1
PROPERTIES OF ∝ PARTICLES
• HELIUM NUCLEUS - +Ve CHARGE
•POSSESS GREAT ENERGY - 5.3 MeV
•HIGH INITIAL VELOCITY
•CAUSE INTENSE IONISATION
•SHORT RANGE – 4-5 CM
PROPERTIES OF β PARTICLES• AN ELECTRON
• HIGH SPEED
• SMALL MASS - EASILY DEFLECTED
• HAS HALF THE CHARGE OF α PARTICLE
• LESS ABILITY TO IONISE
• COMPARATIVELY LONGER RANGES. – 60” (AIR), 4 MM (AL)
Gamma rays, or high energy photons, are emitted from the nucleus of an atom when it undergoes radioactive decay. The energy of the gamma ray accounts for the difference in energy between the original nucleus and the decay products. Gamma rays typically can have about the same energy as a high energy X ray. Each radioactive isotope has a characteristic gamma-ray energy.
GAMMA RAYS
PROPERTIES OF γ RAYS• FORM OF ELECTRO MAGNETIC RADIATIONS
(WAVE LENGTH 10-8 cms) • SIMILAR TO X - RAYS.• ORIGIN OF γ RAYS -NUCLEUS.• EMITTED DURING TRANSITION FROM
MORE EXCITED STATE TO A LESS EXCITED STATE
• HIGHLY PENETRATING.• MAY CAUSE
– PHOTO - ELECTRIC EFFECT– COMPTON EFFECT– PAIR PRODUCTION
PHOTO ELECTRIC EFFECT• The emission of electrons from matter by
EM radn of certain energies. The energy of the incident radn is tfr in discrete amts (photons) each of magnitude hy. Each photon absorbed will eject an electron provided that the photon energy exceeds a certain value φ -- the wk function. The max KE of the electrons E is then given by E = hv –φ . This is known as Einstein’s Photo electric theory.
PHOTO ELECTRIC EFFECT• A γ PHOTON STRIKES AN ORBITAL ELECTRON
AND KNOCKS THE ELECTRON OUT OF ITS POSN IN THE ATOM.
• ALL OF THE ENERGY IN THE INCIDENT PHOTON IS USED IN REMOVING THE ELECTRON FROM THE ATTRACTION OF THE NUCLEUS AND IN IMPARTING KE TO THE ELECTRON.
• THE PHOTON IS ANNHILIATED BY TFR OF ALL ITS ENRGY TO THE ELECTRON. THE FREED ELECTRON BEHAVES AS A β PARTICLE AND IONISATION PRODUCED BY IT ARE CALLED SECY IONISATIONS.
COMPTON EFFECT• INCOMING PHOTON MAY NOT GIVE UP ITS
COMPLETE ENERGY IN THE COLLISION WITH THE ELECTRON.
• AS A RESULT A LOWER ENERGY PHOTON REMAINS AFTER THE COLLISION, WHICH MAY INTERACT WITH OTHER ELECTRONS AND LOSE ENERGY AFTER EACH COLLISION.
• BUT THE LAST INTERACTION RESULTING FROM IT MUST RESULT IN PHOTOELECTRIC EFFECT.
• USUALLY WITH PHOTONS OF SUFFICIENTLY HIGH ENERGIES (0.1 – 1.0 MeV).
PAIR PRODUCTION
• WHEN THE ENERGY OF γ RADIATION BECOMES > 1.02 MeV, PAIR PRODUCTION IS POSSIBLE.
• IF A HIGH ENERGY PHOTON PASSES CLOSE TO A NUCLEUS, IT CAN BE CONVERTED INTO TWO PARTICLES (ELECTRON AND POSITRON) AT THE SAME INSTANT.
• TAKES PLACE AT A POINT EXTEREMLY CLOSE TO THE NUCLEUS OF A HY ATOM.
• THE PHOTON IS ANHHILIATED IN THE PROCESS AND ALL ENERGY CONVERTS TO THE MASSOF THE PARTICLES + KE.
• ELECTRON AND POSITRON ARE CAPABLE OF PRODUCING IONISATION IN THEIR PATH.
NEUTRON BOMBARDMENT• Neutral• Successive elastic or inelastic
collisions. Scattering. Very eff by hydrogenous mtrl. Good moderation.
• Slow Nu - <100 eV.• Nu Decay – Free space for about 10 –
15 mins then decay to a Proton and Electron.
• A Nu addition increase energy in hy mtrl by 8 MeV.
DISINTEGRATION BY NEUTRON
• NEUTRON CAPTURE CREATES FISSION ( N F).• NEUTRON ENERGY EXCITES UNSTABLE
NUCLEUS– SPLIT IT INTO FAIRLY TWO EQUAL PARTS,EJECTS FREE NU AND RELEASE HUGE ENERGY.235 1 144 90 1
U + N ----- Ba + Kr + 2N +ENERGY
92 0 56 36 0
218 214 4
• Po Pb + He
84 82 2
214 214 0
• Pb Bi + e
82 83 1
226 222 4
NOTE. Ra Rn + He+ γ(0.19 MeV
88 86 2
HALF - LIFEThe time taken by half of the atoms of a RA element to disintegrate is called its half life. After half life, the radioactivity of an element also becomes half of the original value.The half life of Ra is about 1600 yrs, which means that a given sample of Ra will disintegrate half in 1600 yrs. Eg, if we start with 1 gm of Ra today, then half gm of it will disintegrate in 1600 yrs. After another 1600 yrs half of remains will have disintegrated and so on.
HALF LIVES OF VARIOUSELEMENTS
• URANIUM 238 - 4.55 X 10 9 YRS
• POLONIUM 210 - 140 DAYS
• POLONIUM 212 - 3 X 10 -7 SECS
DECAY CURVE OF A TYPICAL RADIO ACTIVE SUBSTANCE
100
90
80
70
60
50
40
30
20
10
00 T 2T 3T 4T 5T 6T 7T 8T 9T 4 8 12 16 20 24 28 32 36
HALF LIVES HOURS
TIME
RA
DIO
AC
TIV
E I
NT
EN
SIT
Y
ARTIFICIAL RADIOACTIVITY
27 4 30 1 • Al + He P + n13 2 15 0
30 30 0• P Si + e15 14 + 1
NOTE EVERY ELEMENT TODAY HAS ISOTOPES AND SOME 800 HAVE BEEN OBTAINED BY VARIOUS TRANSMUTATION PROCESSES.
Nu INDUCED RADIO ACTIVITY
• PRODUCT OF Nu CAPTURE ARE RADIO- ACTIVE.
• AIR – Oxygen and Nitrogen little or no significance.
• SOIL– Na 24- half life about 15 hrs, emits Beta and Gamma of nearly 3 MeV. Mn essential for plant growth capture and produce Mn 56 , half life 2.6 hrs, emits Beta and gamma. Silicon and Al produce silicon 31 (2.6 hrs) and Al 28 (2.5 mins). Although contribute to the imdt activity, would be of no significance of after an hr or so.
Contd
• WATER – Hydrogen from non radio active D2. Cl forms cl 38 and emits Beta and hy energy Gamma ( 4-5Hrs ).
• STRUCTRE MTRL. – Source for induced activity for a short while Cu, Zn and Mn are imp in this case.
FISSION AND FUSION
• THE RELEASE OF NUC ENERGY IN AMTS SUFFICIENT TO CAUSE AN EXPLOSION, REQUIRES THAT THE REACTION SHOULD BE ABLE TO REPRODUCE ITSELF WHEN STARTED.
• TWO TYPES OF NUC INTERACTIONS CAN SATISFY THE CONDITIONS FOR THE PRODUCTION OF LARGE AMTS OF ENERGY IN A SHORT TIME.
• THESE ARE KNOWN AS FISSION AND FUSION.
FISSION• DEFINITION.
• FISSION FRAGMENTS.
• TYPES OF FISSION.
• CRITICAL ENERGY FOR FISSION.
• ENERGY RELEASED.
FISSION
IS A PROCESS,THE REACTING NUCLEUS SPLITS INTO PARTS OF ROUGHLY EQUAL MASS, BOTH OF WHICH HAVE MUCH LOWER ATOMIC NOS AND MASS NOS THAN THE ORIGINAL NUCLEUS. THE REACTION IS ACCOMPANIED BY THE RELEASE OF ENORMOUS QTY OF ENERGY AND VERY IMP, THE EXPULSION OF ONE OR MORE NEUTRONS.
TYPE OF FISSION• THERMAL NEUTRON FISSION (>0.03 eV)
Example-U235
• FAST NEUTRON FISSION (> 1MeV ). U238 UNDERGO FISSION BY FAST NEUTRONS ONLY.
CRITICAL ENERGY FOR FISSION
• ENERGY REQUIRED TO CAUSE SEVERE DEFORMATION OF THE NUCLEUS – CRTICAL DEFORMATION ENERGY (CDE).
• THE ENERGY GAINED UPON ENTRY OF THE NEUTRON AND BINDING ENERGY. BOTH ARE IMPORTANT IN DETERMINING THE EASE OF FISSION.
• CDE DEPENDS UPON THE RELATIONSHIP BETWEEN THE MASS NO AND THE ATOMIC NO OF THE NUCLEUS.
C- ENERGY FOR FISSION
• CRITICAL DEFORMATION ENERGY (CDE) - DEPENDS ON ATOMIC AND MAS NUMBERS
CDE REQURIED KE REQUIRED
FOR FISSION FOR FISSION
U 238 6.5 MEV HIGH ENERGY 1.0 MEV
U 235 6.1 MEV
THERMALNEUTRONS
(0.03 EV)
U 233 6 MEV THERMAL NEUTRONS
ENERGY RELEASED - FISSION
• AVG ENERGY PER FISSION = 200 MEV
• MASS DEFECT METHOD.
92U235 + 0N 1 42Mo95 + 57La139 + 2 0N1
• MASS OF 92 U235 = 235.124 MU
• MASS OF 0N1 = 1.009 MU
• TOTAL =236.133 MU
• MASS OF 42 Mo 95 = 94.946 MU
• MASS OF 57 LA 139 = 138.955 MU
• MASS OF 2 X 0N1 = 2.018 MU• TOTAL 235.919 MU• MASS DEFECT = 236.133 - 235.919 = 0.214 MU.
ENERGY RELEASED = 0.214 X 931 = 200 MEV PER FISSION. (931 IS THE CONVERSION
FACTOR)
CHAIN REACTIONIT IS THE PROCESS IN WHICH THE NUMBER OF NEUTRONS KEEP ON MULTIPLYING RAPIDLY (IN A GEOMETRIC PROGRESSION) DURING FISSION TILL THE ENTIRE FISSIONABLE MATERIAL IS EXHAUSTED
U 235 CHAIN REACTION• WHEN A U235 NUCLEI IS BOMBARDED BY A
NEUTRON, TWO OR MORE NEUTRONS ARE RELEASED WHICH FURTHER BOMBARD OTHER NUCLEI.
• IT TAKES MINIMUM OF 80 CYCLES FOR ONE KG OF U235 TO BREAK DOWN INTO ITS CONSTITUENT NUCLEONS.
• THEREFORE 280 REACTIONS TAKES PLACE.
• AVG TIME TAKEN TO CAUSE SPLITTING = 10 -8 SEC.
CRITICAL MASS•DEFINITION
QTY OF FISSILE MTRL REQD SO THAT CHAIN REACTION JUST BECOMES SELF SUSTAINING.
REPRODUCTION FACTOR HAS TO BE MORE THAN UNITY
•DEPENDS UPON:--
DENSITY.
PURITY.
SHAPE AND SIZE - SPHERICAL (MIN SURFACE AREA FOR A GIVEN VOL).
WPN DESIGN - USE OF REFLECTORS.
NEUTRON PRODUCTION AND ESCAPE RATIO
• NEUTRONS PRODUCED IS PROPOTIONAL TO THE NO OF FISSIONS, WHICH IN TURN IS PROPOTIONAL TO THE NO OF FISSILE ATOMS.(MASS OF THE FISSILE MTRL).
• FOR A SPHERE OF A PURE FISSILE MTRLOF RADIUS R,- SURFACE AREA = 4 π R2
- MASS =4/3 π R3 X DENSITY• THE RATIO OF NEUTRONS ESCAPING TO NO OF
NEUTRONS PRODUCED WILL VARY AS PER –= SURFACE AREA /MASS= 3 / R X DENSITY
NEUTRON PRODUCTION AND ESCAPE RATIO (CONTD)
HENCE , INCR IN EITHER RADIUS OR DENSITY OR BOTH WILL REDUCE THE PROPORTION OF THE ESCAPING NEUTRONS AND INCR THE LIKELYHOOD OF A CHAIN REACTION.
REFLECTION OF NEUTRONS
• REFLECTORS. USED IN WEAPONS TO REFLECT BACK THE NEUTRONS INTO THE SYSTEM. HIGH DENSITY ATOMIC MASS MTRLS – U235.
• MODERATORS. USED IN REACTORS TO SLOW DOWN AND SCATTER BACK THE NEUTRONS INTO THE SYSTEM. LOW ATOMIC MASS ELEMENTS LIKE –CARBON, BERYLLIUM, GRAPHITE RODS.
TYPICAL FISSION PRODUCTS
92U235
40ZR97
41Nb97
42Mo97
52Te137
53 I137
54Xe137
55Cs137
56Ba137
40 PROTONS
57 NEUTRONS
41 PROTONS
56 NEUTRONS
42 PROTONS
55 NEUTRONS STABLE
52 PROTONS
85 NEUTRONS
53 PROTONS
84 NEUTRONS
54 PROTONS
83 NEUTRONS
55 PROTONS
82 NEUTRONS
56 PROTONS
81 NEUTRONSSTABLE
-β
-β
-β
-β
1 MIN
22.5 SEC
3.4 MIN
ABOUT 27 YRS
17 HRS
75 MIN
-β
-β
NEUTRON
92 PROTONS
143 NEUTRONS
Zirconium / Tellurium
Niobirium
Molydbynum
Iodine
Xenon
Cesium
Barium
NUCLEAR-FUSIONTHE COMBINATION OF VERY LIGHT
NUCLEI LOW IN MASS NUMBER INTO A HEAVY NUCLEI ALONG WITH RELEASE OF ENORMOUS ENERGY IS CALLED NUCLEAR FUSION.
FUSION THE COMBINATION OF VERY LIGHT
NUCLEI, LOW IN MASS NUMBER INTO PRODUCT NUCLEI THAT ARE NEARER THE MIDDLE OF SCALE, FORMS THE FUSION PROCESS.
(BECAUSE THE FIRST THOUGHTS IN THIS FIELD WERE DIRECTED TOWARDS THE USE OF THE LIGHTEST OF ALL NUCLEI HYDROGEN, THE EARLIEST EXPLOSIONS PRODUCTED BY THIS MEANS WERE POPULARLY TERMED HYDROGEN EXPLOSIONS)
PRACTICAL CONSIDERATIONS FOR FUSION PROCESS
• HIGH TEMP (SEVERAL MILLION DEG C) REQD TO ACCOMPLISH FUSION REACTION.
• DIFFICULT TO MAINTAIN SUCH HIGH TEMP FOR LONG DURATIONS.
• THEREFORE REQMT OF GREATEST ENERGY RELEASE IN THE LEAST TIME.
POSSIBLE MTRL FOR FUSION PROCESS
• ORIDINARY HYDROGEN IS NOT SUITABLE AS ENERGY PRODUCING REACTIONS INVOLVE SLOW NUC CHANGES.
• 1H2 AND 1H3 SHOW MORE PROMISE AS FUELS.
1H2 EXISTS IN ORDINARY WATER (0.015%), AND IS GEN USED.
• 1H3 IS MANMADE, AND VERY EXPENSIVE TO PRODUCE. ALSO IT HAS A HALF LIFE OF ONLY 12 ½ YRS .
• ALTERNATIVELY 1H3 CAN BE PRODUCED IN A NUC REACTOR BY IRRADIATION OF 3LI6.
ENERGY RELEASED - FUSION
• 1lb OF 1 H2 = 26000 TONS TNT.
• 4 KG LI 6D - POSSIBLE REACTIONS
1H3 + 1H22HE4 + 0N1 + 17.6 MeV
1H2 + 1H22HE3 + 0N1 + 3.2 MeV
1H2 + 1H2 2HE3 + 20N1 + 4.O MeV
5 x 1H2 ATOMS - ENERGY RELEASED 24.8 MeV
…contd
• 4 KG LI 6D CONTAINS 1 KG 1H 2
ENERGY RELEASE
• COMPARISON = 5.7 X 10 4 TONS TNT = 57 KT
• 1 KG URANIUM 100% EFFICIENCY = 20 KT THUS FUSION:FISSION = 57 KT : 20 KT FOR 1 KG FUEL.